Robotic dispensing systems, which can be used to dispense an adhesive, sealant or similar material as a bead along a path, can include a robot arm that moves with respect to a substrate upon which the material is to be applied. In bead dispensing applications, there is a need to measure the width and height of the bead as the material is being dispensed along the bead path. Because of the difficulty in robot programming, it is undesirable to turn robot tooling, such as the nozzle that is dispensing the material, so that the bead is dispensed in the same travel direction of the nozzle along the entire bead path. For example, when the bead path is to take 90 degree left turn on the substrate, the nozzle on the robot likely will not be rotated 90 degrees at the corner of the turn, but instead the robot arm will simply change the direction in which the nozzle was traveling.
To accommodate for the changing direction of the bead path and the need to measure the width and height of the bead, known bead measurement devices employ at least three cameras angularly spaced equidistantly from one another around the central axis of the nozzle. By providing at least three cameras, each camera can have a field of view of about 120 degree so that a 360 degree view around the nozzle is provided. In addition to the expense of providing three cameras and the size of the fixture to accommodate three cameras, other problems associated with using three cameras in such a measurement system are discussed in U.S. Pat. No. 8,538,125 B2.